Hydrazine manufacture

ABSTRACT

Hydrazine is produced in a two chamber electrolytic cell with anode and cathode chambers separated by an ion exchange membrane. When using an anion exchange membrane, ammonia and nonaqueous solvent are fed to the cathode compartment and hydrazine and solvent are collected from the anode compartment. When using a cation exchange membrane ammonia and nonaqueous solvent are fed to the anode compartment while hydrazine is also removed from the anode compartment. Similarly, alkyl hydrazines can be produced by feeding a lower alkyl amine instead of ammonia.

United States Patent [72] Inventors Stuart G. McGriff Alexandria, Va.;Wayne A. McRae, Lexington, Mass. [21] Appl. No. 870,920 [22] Filed Sept.16, 1969 [23] Division of Ser. No. 542,780, Apr. 15,

1966, Pat. No. 3,496,091 [45] Patented Oct. 26, 1971 [73] AssigneeIonics, Incorporated Water-town, Mass.

[54] HYDRAZINE MANUFACTURE 7 Claims, 6 Drawing Figs.

[52] US. Cl 204/59, 204/101, 204/102, 204/180 P [51] 1nt.Cl 801k 3/00,BOlk 3/08, BOlk 3/10 [50] Field of Search 204/180 P, 101, 102,59; 23/190[56] References Cited UNITED STATES PATENTS 2,813,067 11/1957 Stuart204/59 2,841,543 7/1958 Haller 204/59 3,034,861 5/1962 Pursley 23/1903,251,755 5/1966 Mayland et al. 204/101 3,268,425 8/1966 Pursley....204/59 3,280,015 10/1966 Chu 204/101 3,281,211 10/1966 Lacey 23/1903,301,773 1/1967 Whitney 204/101 Primary Examiner-John H. Mack AssistantExaminer-A. C. Prescott Attorneys-Aaron Tushin and Norman E. SalibaPATENTED B 2619?! 3,816,131 2 SHEET 10F 2 INVENTORS FIG I STUART 6. MCGRIFF WAYNE A. MC RAE B 77MB, J

ATTORNEY PATENTEDUCT 2619?! 3.616312 SHEET 2 F 2 FIG?) 5 FIG.4

SOLVENT+ HYDRAZINE (N2+NH3) 28 so 26 27 28 24 22 L 1 l T PURE SOLVENT/\'J\fL'---+- A #Nm- [\AAAA/ SOLVENT+AMMONIA I I i a T1 I A-ANIONPERMSELECTIVE 28 3O 28 23 MEMBRANE H6 5 SOLVENT+ AMMONIA+ H2 C-CATIONPERMSELECTIVE M MBRANE SOLVENT HYDRAZINE SOLVENT AMMONIA (N NH;)

8E5 3o 2a Ml gs 3 u 24 YI/VVVW A T C 4 INVENTORS r-- STUART 0. MC GRIFF21 L I WAYNE A.MC RAE 1 l 30 SOLVENT+ AMMONIA BY +Hz MM 4M PURE SOLVENTH ATTORNEY HYDRAZINE MANUFACTURE This application is a division of Ser.No. 542,780 filed Apr. l5, 1966 now U.S. Pat. No. 3,496,091.

This invention relates to novel apparatus and methods for producinghydrazine by the electrolysis of ammonia solutions and, in particular,to electrolytic cells utilizing electrolytes of solid ion-exchangematerial for the production of anhydrous hydrazine.

Hydrazine (M,M finds its greatest use as a rocket fuel, but also as anoxygen scavenger in boiler water; as an intermediate in drugmanufacture; as a plant growth retardant and in rubber blowing. Therecent developments in new catalysts make hydrazine of increasinginterest as a monopropellant and as a source of energy for fuel cellapplications. However, the present cost of hydrazine is too high forwidespread commercial use.

Almost all of the present production of hydrazine is based on thechemical oxidation of ammonia or urea in aqueous solutions by employingan oxidizing agent of an alkaline hypochlorite. The hydrazine isobtained as a dilute aqueous solution containing many contaminants andthe commercial product of hydrazine hydrate or anhydrous hydrazine isproduced with difficulty and great expense. Attempts have been made toproduce hydrazine by electrolysis, using a variety of operatingconditions and starting materials, but none appear to be sufficientlyinexpensive for general use.

In the electrolysis of liquid ammonia, hydrazine is one of the firstproducts formed by the anodic oxidation of ammonia. Liquid ammonia, likepure water, is a poor electrical conductor and is only slightly ionizedinto ammonium and amide ions, as shown in the following reaction: ZNH ZNl-I[+NH During the electrolysis, the negatively charged amide ions aredischarged by oxidation at the anode with a pair combining to formhydrazine. However, because of the poor conductance of liquid ammonia,the prior art has resorted to adding soluble electrolytes to the ammoniato form a solution having increased electrical conductance. Suchelectrolytes, soluble in liquid ammonia, include, for example, s oda;nide, (Na NH sodium hydroxide, ammonium salts, including ammoniumsulfonate and urea. Although the high degree of dissociation of theelectrolytes do in fact increase the electrical conductivity of theresulting solution, their presence can be detrimental to the productionof hydrazine.

Hydrazine is thermodynamically usable" and" therefore readilysusceptible to decomposition. Since hydrazine is more susceptible tooxidation than ammonia, the hydrazine formed at the anode, if allowed toremain in the area of the anode, will quickly decompose. Many materialsare known that will catalyze or accelerate this decomposition, suchmaterials being halide ions, heavy metal ions and strong protonacceptors, such as the amide and hydroxide ions. Additionally, certainmaterials used in the construction of the anodes will more readilychemisorb hydrazine with its resultant decomposition.

In accordance with the present invention, solutions of ammonia incontact with an electrolyte of solid ion-exchange material are subjectedto electrolysis to produce hydrazine at the anode. The electrolyticapparatus has a continuous bridge of a solid ion-exchange resin betweenand in intimate contact with the spaced cathode and anode electrodes.The ionexchange material bridging the space between the electrodes willfunction to provide an hydroxide conducting path since the ammoniasolution passing into the cell will have a high electrical resistance.In the equilibrium between the ionexchange resin and a solution, theconcentration of mobile ions in the resin is not highly dependent uponthe concentration of ions in the surrounding solution, but isessentially determined by the number of exchange sites within the resinitself. Thus, in the case of an anion-permeable resin, it is possible tohave a high concentration of mobile negatively charged am e iqiistN iill ifi ifll wjll to Obtain r q i d electrical conductance without theaddition of soluble salts or electrolytes to the ambient solution. Thistechnique provides an available source of amide ions. The hydrazineformed at the anode will dissolve in the liquid, and the resultingsolution will be removed from the cell before there is an substantialcontact between the hydrazine in solution and amide ions in the resin.The result of this process is that hydrazine is formed in the liquidsolution with the solution isolating the hydrazine from contact withcatolytic materials which would cause excessive decomposition.

Therefore, the object of this invention is to provide a novel apparatusand process to produce hydrazine economically from liquid ammoniasolutions by electrolysis.

A further object is to produce hydrazine derivatives the the processapplicable to hydrazine by substituting amines in place of ammonia.

A further object is to economically prevent the further decomposition oroxidation of hydrazine once it is electrolytically formed.

A further object is to utilize a solid electrolyte of ionexchange resinin contact with ammonia to manufacture hydrazine electrolytically.

A further object is to employ a semiconducting anode forelectrolytically oxidizing ammonia into hydrazine.

These and various other objects, features and advantages of theinvention will appear more fully from the detailed description whichfollows accompanied by the drawings. To better understand the invention,the description is made with specific reference to certain preferredembodiments; however, it is not to be construed as limited theretoexcept as defined in the appended claims. By way of example, the use ofthis invention will now be described in detail with reference to theaccompanying drawings in which:

FIG. 1 is an exploded perspective view of one embodiment of the improvedelectrolytic cell of the present invention wherein the solid electrolyteof ion-exchange resin is in the fonn of a membrane having pebbledsurfaces.

FIG. 2 is a sectional view of an assembled cell taken along lines 2-2 ofFIG. 1, showing the membrane in contact with both electrodes.

FIG. 3 is a modification of an ion-exchange membrane in which both sideshave a corrugated design.

FIG. 4 is a cross-sectional view of a corrugated ionexchange membranetaken along line 4-4 of FIG. 3.

FIG. 5 illustrated schematically the process for producing hydrazineelectrolytically by employing an anion-selective membrane in theelectrolytic cell and FIG. 6 illustrates schematically an alternateprocess using a cation-selective membrane.

As shown in the drawings and, in particular, in FIGS. 1 and 2, theelectrolytic cell is basically of a package or stack type. The apparatuscomprises a cathode 1, an anode 3, an embossed or contouredion-permselective membrane 5 and spacer members 6, all of which areassembled between two terminal pressure end plates 7 and 8. A fluidtightstack is obtained by applying the proper pressure against each endplate, as by bolts 9 and nuts 10. Means for passing a DC potentialtransversely through the stack is provided for through leads I l and 12from an outside source of electric current (not shown).

The spacer members 6 are generally of an electrically nonconductingplastic gasketing material such as polyethylene and have cutout centralportions 13 and 14 which form the cathode and anode fluid-holdingchambers, respectively. These chambers are confined by the frame orborder 15 of the spacer which also functions to separate and gasket thesubstantially flat marginal area 25 of the membrane with respect to theadjacent electrodes 1 and 3. The spacers, electrodes and end plates areshown with apertures 16 for directing a fluid to the cathode and anodechambers 13 and I4 and further apertures 17 are provided for withdrawingfluid therefrom. The apertures 16 and l! in the frame 15 of the spacerare located on substantially opposite sides of the cutout flow area. Theapertures 16 and 17 in the frame of the spacer communicate with therespective cathode and anode chamhere by slits or channels 20 cut in thespacer material. Inlet means for passing fluid into the cathode andanode chambers are provided by inlets 20 and 22 respectively, and outletmeans for withdrawing the solutions are provided at 23 and 24. Thecombination of a cathode and an anode chamber, membrane and terminalelectrodes form a single electrolytic unit.

The single membrane 5 separating the electrode chambers 13 and 14 fromeach other is fabricated from an organic polymeric cross-linked materialand may be anion permselective or cation perselective, both types ofmaterial being well known in the art.

The manufacture and properties of ion-selective membranes are fullydisclosed in U.S. Pat. Nos. 2,702,272; 2,703;768; 2,73l,408; 2,800,445;Re. 24,865, and many others. Ion-exchange membranes are comprised of asolvated ion-exchange resin generally in sheet form which may bereinforced by an inert woven fabric structure. Such membranes generallycomprise about 30 percent fabric by weight, 40 percent resin, and about30 percent solvent, the solvent being uniformly dispersed throughout theresin.

Cation membranes are typically cross-linked sulfonated polystyrene. Inthe presence of inbibed solvent having at least a moderate dielectricconstant, for example, dimethyl formamide, the sulfonate groups aredissociated into bound negatively charged ions and mobile positivelycharged counterions. The positively charged counter-ions are free todiffuse through the resin structure and, under the influence of anelectric potential, are substantially the sole carrier of current.Typical positively charged counter-ions, for example, are sodium andammonium. Similarly, the anion membranes may be a cross-linkedpolystyrene structure with quaternary ammonium salt groups whichdissociate into bound positively charged quaternary ammonium ions andmobile negatively charged counter-ions such as, for example, hydroxide,sulfate and, in some nonaqueous solvents, the amide ion.

Generally, conventional ion-selective membranes are fabricated as sheetshaving totally flat surfaces. However, the membranes of the presentinvention are provided on both major faces with an elevated central areaintegrated with and generally of the same polymeric ion-exchangematerial as the substantially flat marginal sealing area 25 of themembrane to form a single homogeneous piece. The surface of the centralarea is embossed or contoured with a plurality of projecting 26 andreceding 27 portions. The receding portions are so arranged as to formflow channels 28 between the projections for the passage of fluidtherethrough. As shown in the drawings, the contoured central area ofthe membrane is pebbled (FIG. I) or corrugated (H6. 3) but other variousgeometric designs, such as ribs, studs, ridges and the like may beprovided on the surface.

When the elements comprising the electrolytic cell are as sembled into afluidtight stack arrangement, the projecting central portions 26 of themembrane will extend directly into the central cutout portions 13 and 14of the adjacent spacers which form the cathode and anode chambers. Theprojections may be about the same height as the spacer thickness. Theheight of the projections may vary within wide limits but an extensionof about 30 mils (0.030 inches) in a direction perpendicular to the flatsurface of the membrane would be satisfactory. Such a membrane embossedon both sides and having a 30 mil thickness across the flat marginalarea would than have a total central area thickness of about 90 mils. Onassembly of the cell, the tips of the projections are caused to pressfirmly against the surface of each adjacent electrode to form anelectrode'membrane interface 30 which makes electrical contact and formsa continuous ion-conducting bridge between the electrode pair. Thisarrangement will allow an electric current to be carried between theelectrodes, primarily by mobile ions of one sign passing solely throughthe membrane structure. The recessed areas or interstices between theprojections form fluid-flow channels 28. The fluids used in the cellneed not necessarily be electrolytically conducting since the electriccurrent will be carried within and across the bridge of ion-conductingmembrane material. The membranes can of course be of various thicknessesand have pattern configurations other than those specifically describedherein. All other factors being equal, it is evident that the greaterthe number of projections of membrane area contacting the electrodesurface, the smaller the power consumption of the electrolytic cell.

The membranes may be fabricated by sandwiching the liquid polymer mixbetween two glass plates having the desired patterned surface,polymerizing the mix until solid, and then stripping off the glassmolding plates to leave a solid polymerized structure. The patternserves as the mold for the contoured central portion of the membrane.There are glass molding plates of numerous design patterns which areavailable commercially. The solid structure is then treated withappropriate chemicals to make them either anion or cation permselectiveas by quarternization or sulfonation. in order to add strength andflexibility to the membrane, an inert sheet of open-weave cloth orscreen material may be incorporated as a backing or reinforcing materialwithin the membrane. in such a method, the liquid mix is poured over thecloth fabric prior to being sandwiched between the glass molding plates.Additionally, in order to prevent or minimize fracturing of theprojecting or raised portions of the membrane, especially duringassembly of the electrolytic cell when the membrane is com pressedbetween the pair of electrodes. It is preferable that bits of fabricmaterial or fibers of glass or other material be suspended in the liquidpolymer mix before casting into a membrane. These fibers willstructurally reinforce the entire raised membrane area to impart thenecessary resistance to cracking.

The operation of the electrolytic apparatus, for example, in themanufacture of hydrazine from ammonia, may be illustrated by referringparticularly to H0. 5 wherein the membrane is anion-selective and themobile counter-ions are amide ions N11,).

A catholytic and an anolytic feed solution are directed into inlet 21and 22 respectively, and caused to flow into the respective cathode andanode chambers across the chambers via the interstices or flow channels28 formed by the projecting membrane portions and out of the chamber byway of outlets 23 and 24 in the general direction as shown by the arrowsof the figures.

The catholytic feed solution is comprised of a nonaqueous inert fluidsolvent containing ammonia in dilute concentrations. The feed to theanode chamber is pure anhydrous fluid solvent. The fluid solvent shouldof course be a solvent for ammonia and hydrazine and, preferably, shouldhave at least a moderate dielectric constant and have a negligibleaffinity for protons, and should not substantially dissociate into ananion which would have a strong afi'mity for protons. Another preferredrequirement of the solvent is that it has a higher boiling point thanthat of liquid hydrazine (B.P. 113.5 C.). This requirement evolves fromthe consideration of recovering the hydrazine from the mixture ofhydrazine and solvent issuing as the effluent of the anode chamber.Distillation is a preferred method since two liquids are involved and ofcourse recovery cost will be minimized if the hydrazine has asubstantially lower boiling point that the solvent to allow its beingboiled off from the bulk of solvent. Suitable solvents meeting thepreferred requirement are dimethyl acetamide, dimethyl formamide,dimethyl sulfoxide, and the like.

The electrolysis is carried out using a source of direct current andsuitable electrode current densities. A range of about 10 and amps/ft ispreferred although current densities outside this range are suitable.During electrolysis, the ammonia in the catholytic solution is reducedat the cathodemembrane interface into hydrogen gas and amide ions asfollows:

2NH 2e- 2NH, H, The hydrogen gas is carried out of the chamber with theflow ing catholytic solution. This catholytic solution, now partiallydepleted in ammonia, is removed from the cell at exit 23 and directed toa gasJiquid separator (not shown) for removal of the hydrogen gas. Thesolution may then be spiked with additional gaseous or liquid ammoniaand recycled back to the cathode chamber of the cell for furtherprocessing.

The negatively charged amide ions formed at the cathode will, under theinfluence of the electric current, migrate across theanion-permselective membrane in the direction of the positively chargedanode. On reaching the anode-membrane interface, oxidation of the amideion will occur with a pair of amide ions combining to form hydrazine asfollows:

ZNHQ-fNJi 2c In addition, small amounts of nitrogen and ammonia may alsoresult as products of the oxidation process. The hydrazine formeddiffuses out of the membrane, and is carried out of the anode chamberwith the flowing solvent to a gas separator (not shown) to remove anynitrogen gas contained therein. The dissolved hydrazine is thenseparated from the remaining solution by any suitable means, such asdistillation, freezing, membrane permeation, or the like. The preferredmethod would be distillation whereby the solution is stripped of itsanhydrous hydrazine and traces of ammonia. Small amounts of hydrazinehydrate may be present in the final product due to unavoidable pickup ofwater in the system. The ammonia, separated during distillation, may beadded to the catholytic feed solution, and the pure solvent remaining isrecycled as the feed solution to the anode chamber.

It is important that the hydrazine formed be removed from the vicinityof the anode as quickly as possible. if allowed to remain within theanode area, the hydrazine becomes susceptible to oxidation and canreadily decompose as follows:

The extent of hydrazine decomposition depends among other things on theanode current density and the concentration of the reactants present atthe anodemembrane interface. Where the cell employs ananion-permeselective membrane, the reactants would be hydrazine alongwith amide ions, and naturally the lower their concentration at theinterface, the less hydrazine decomposition. Further prevention ofhydrazine decomposition can be attained by fabricating the anodes from amaterial on which hydrazine is not readily chemisorbed. Such anodes maybe constructed of impervious graphite, platinum, electrolytic valvemetals, such as titanium coated with a precious metal of platinum, andthe like. In place of these conventional electrodes, it is furthercontemplated that semiconducting electrodes be employed to furtherdiminish the hydrazine decomposition process. The preferred material forsemiconducting electrodes is impervious self-bonding carbide havingeither the nor p-type conduction. Hydrazine will be less stronglyabsorbed on properly constructed semiconducting electrodes and thereforeless subject to electro-oxidation or decomposition.

The ion-exchange resin of the membrane does not act as a catalyst in thedecomposition of hydrazine. In fact, in its use as the electrolyte ofthe cell, the concentration at the anode of strong proton acceptors,such as the amide ion, is kept at a low level since the only amide ionscontacting the anode are those carrying the electric current in theirmigration through the ion-exchang e membrane. Additionally, since themobile amide ion is the only conducting ionic species within the anionselective resin which need be present in the process, hydrazinedecomposition attributable to heavy metal ions or halides will not occuras would be the case where soluble salts are employed as the electrolyteof the cell.

An alternate embodiment of the invention is diagrammatically illustratedin FlG. 6. The membrane in this modification is cation selective and isin the ammonium ionic form NHJ). Operation of this cell is similar tothat of FIG. 5 except that the feed solutions entering the electrodechambers are reversed; that is, the solution of solvent and ammonia isfed to the anode chamber, whereas the pure anhydrous-solvent is fed tothe cathode chamber. In the anode chamber, the ammonia is oxidized atthe anode-membrane interface to hydrazine and positively chargedammonium ions as follows:

To minimize the decomposition of the hydrazine, an excess of ammonia ismaintained at the membrane surface. Since ammonia is a stronger basethan hydrazine, the hydrazine will be in the free base form and diffuseout of the resin to be carried out of the anode chamber by the flowinganolyte.

The positively charged ammonium ions formed at the anode will migratethrough the cation membrane in the direction of the cathode where theywill be cathodically reduced at the cathode-membrane interface toammonium and hydrogen gas as follows:

The hydrogen gas is then separated from the anolyte effluent solution,the solution is spiked with additional ammonia and the resultingsolution of solvent and ammonia is recycled back to the cell as the feedto the anode chamber.

The following examples are further illustrative of the practice of thisinvention and are not intended to be limiting:

EXAMPLE I In a cell constructed as shown in FIG. 5, the membrane is atrimethylaminated, chloromethylated copolymer of ethyl vinyl benzene anddivinyl benzene reinforced with woven polypropylene fabric. The fixedcharged groups are quaternary ammonium cations (benzyl trimethylammonium). The total thickness of the membrane is about 0.090 inch. Theplane of the membrane is vertical and the surfaces of the membrane inthe central portion are raised into ribs having a roughly triangularcross section and having their long dimension in a vertical direction.The ribs project about 0.030 inch from the bulk of the membrane and areon centers of about 0.035 inch. The central portion of the membrane isabout 2 inches wide and 7 inches long. The flow in each compartment isupward. The electrodes are smooth platinum and the spacer gaskets arepolypropylene. The membrane is converted to the hydroxide form in waterin the conventional way and then equilibrated with several changes ofmethanol to replace the water and with several changes of dimethylformamide to replace the methanol. The membrane is then assembled intothe cell. To convert the membrane to the amide fonn, a 5 percentsolution of sodium amide in anhydrous dimethyl formamide is passedupwardly through the cathode compartment at a rate of about 3 grams perminute. Pure anhydrous dimethyl formamide is passed upwardly through theanode compartment at a rate of about 3 grams per minute. A current of 3amperes is applied for 2 "hours and then the current is turned off andthe compartments rinsed with anhydrous dimethyl formamide. In aproduction run the catholyte is anhydrous dimethyl formamide containingabout 5 percent anhydrous ammonia by weight. The catholyte flows at arate of about 3 grams per minute. The anolyte is anhydrous dimethylformamide and flows at a rate of about 3 grams per minute. A current ofabout 3 amperes is applied. After about 3 hours, about l grams ofenolyte efiluent have been collected. Upon analysis by standard iodatesolution using amaranth as an indicator, it is found that the collectedanolyte contains about 3.75 grams of hydrazine. The current efficiencyis about 70 percent. The hydrazine is recovered by fractionaldistillation.

EXAMPLE 2 in a cell constructed as shown in FIG. 6, the membrane is asulfonated terpolymer of vinyl toluene, ethyl vinyl benzene and divinylbenzene reinforced with a woven fabric of glass fibers. The fixedcharged groups are sulfonate anions. The total thickness of the membraneis about 0.090 inch. The plane of the membrane is horizontal and thesurfaces of the membrane in the central portion are raised into smallhillocks rising about 0.030 inch from the surface of the membrane. Thehillocks are about 0.060 inch in diameter and are on centers of about0.075 inch. The central portion of the membrane is about 2 inches wideand 7 inches long. The flow in each compartment is horizontal and in acomposite direction parallol to the long dimension of the centralportion. The electrodes are self-bonded silicon carbide having n-typecarriers. The gaskets are polytetrafluorethylene. The membrane isconverted to the ammonium form in water in the conventional way and thenequilibrated with several changes of methanol to replace the water andwith several changes of dimethyl acetamide to replace the methanol. Themembrane is then assembled into the cell. In a production run, thecatholyte is anhydrous dimethyl acetamide, flowing at a rate of about 3grams per minute. The enolyte is anhydrous dimethyl acetamide containingabout 5 percent anhydrous ammonia by weight. The anolyte flows at a rateof about 3 grams per minute. A current of about 3 amperes is applied.The product of the first two hours of operation is discarded and theproduct of the anolyte of the next three hours is collected. The amountcollected is about 180 grams. Upon analysis by standard iodate solutionusing amaranth as an indicator, it is found that the collected anolytecontains about 3.20 grams of hydrazine. The current efficiency is about60 percent. The hydrazine is recovered by fractional distillation.

EXAMPLE 3 The cell of example 2 is operated with percent methyl amine inanhydrous dimethyl sulfoxide as the anolyte and impervious graphiteelectrodes. The catholyte is anhydrous dimethyl sulfoxide. Dimethylhydrazine (probably the symmetrical compound) is recovered from theanolyte. The current efflciency is about 70 percent.

What is claimed is:

l. A process of electrolytically producing hydrazine from ammonia in atwo-chamber cell having a terminal anode and cathode electrode andadjacently disposed anode and cathode chambers separated from oneanother by an ion-permselective membrane comprising, passing anammonia-containing, nonaqueous fluid solvent into that electrode chamberwhich is adjacent to the electrode having a charge opposite in sign tothe fixed charge on said membrane passing fluid solvent into said otherelectrode chamber, passing a direct current across the electrodesthrough said chambers and membrane to cause the anodic formation ofhydrazine, withdrawing the resulting anolyte solution from said chamber,and separating and recovering said hydrazine from said anolyte solution.

2. The process of claim 1 wherein the fluid solvent is selected from thegroup consisting of dimethyl formamide, dimethyl acetamide, dimethylsulfoxide and mixtures thereof.

3. The process of claim 1 wherein the hydrazine is separated andrecovered from the withdrawn anloyte solution by distillation.

4. The process of claim 1 wherein the membrane is cationpermselectiveand wherein the ammonia-containing fluid solvent is passed into saidanode chamber and the fluid solvent into said cathode chamber.

5. The process of claim 1 wherein the membrane is anionpermselective andwherein the ammonia-containing fluid solvent is passed into said cathodechamber and the fluid solvent into said anode chamber.

6. A process of electrolytically producing alkyl hydrazines in atwo-chamber cell having a terminal anode and cathode electrode andadjacently permselective membrane comprising, passing a nonaqueous fluidsolvent containing a lower alkyl amine into that electrode chamber whichis adjacent to the electrode having a charge opposite in sign to thefixed charge on said membrane, passing fluid solvent into said otherelectrode chamber, passing a direct current across the electrodesthrough said chambers and membrane to cause the anodic formation of alower alkyl hyrazine, withdrawing the resulting anolyte solution fromsaid chamber, and separating and recovering said alkyl hydrazine fromsaid anolyte solution.

7. The process of claim 6 wherein the lower alkyl amine is methyl amineand the fluid solvent in dimethyl sulfoxide.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 16,31 Dated October 26 1971 Inventor) Stuart G McGriff et a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 8, line 23, after "adjacently" insert disposed anode and cathodechambers separated from one another by an ion Signed and sealed this29th day of August 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents RM Po-1050(10-69) UScOMM-DC wan-Pun 9 U S GOVERNMENT PRINTINGOFFICE l9! D36i 3J4

2. The process of claim 1 wherein the fluid solvent is selected from thegroup consisting of dimethyl formamide, dimethyl acetamide, dimethylsulfoxide and mixtures thereof.
 3. The process of claim 1 wherein thehydrazine is separated and recovered from the withdrawn anloyte solutionby distillation.
 4. The process of claim 1 wherein the membrane iscation-permselective and wherein the ammonia-containing fluid solvent ispassed into said anode chamber and the fluid solvent into said cathodechamber.
 5. The process of claim 1 wherein the membrane isanion-permselective and wherein the ammonia-containing fluid solvent ispassed into said cathode chamber and the fluid solvent into said anodechamber.
 6. A process of electrolytically producing alkyl hydrazines ina two-chamber cell having a terminal anode and cathode electrode andadjacently permselective membrane comprising, passing a nonaqueous fluidsolvent containing a lower alkyl amine into that electrode chamber whichis adjacent to the electrode having a charge opposite in sign to thefixed charge on said membrane, passing fluid solvent into said otherelectrode chamber, passing a direct current across the electrodesthrough said chambers and membrane to cause the anodic formation of alower alkyl hyrazine, withdrawing the resulting anolyte solution fromsaid chamber, and separating and recovering said alkyl hydrazine fromsaid anolyte solution.
 7. The process of claim 6 wherein the lower alkylamine is methyl amine and the fluid solvent in dimethyl sulfoxide.